7.8 回归中的相关度和R平方值应用

最新推荐文章于 2023-01-08 15:54:59 发布

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最新推荐文章于 2023-01-08 15:54:59 发布

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import numpy as np
from astropy.units import Ybarn
import math

def computeCorrelation(X,Y):
    xBar = np.mean(X)
    yBar = np.mean(Y)
    SSR = 0
    varX = 0
    varY = 0
    for i in range(0,len(X)):
        diffXXBar = X[i] - xBar
        diffYYBar = Y[i] - yBar
        SSR += (diffXXBar * diffYYBar)
        varX += diffXXBar ** 2
        varY += diffYYBar ** 2
        
    SST = math.sqrt(varX * varY)
    return SSR / SST
    
def polyfit(x,y,degree):
    results = {}
    coeffs = np.polyfit(x,y,degree)
    results['polynomial'] = coeffs.tolist()
    
    p = np.poly1d(coeffs)
    yhat = p(x)
    ybar = np.sum(y)/len(y)
    ssreg = np.sum((yhat-ybar)**2)
    print "ssreg: ",str(ssreg)
    sstot = np.sum((y - ybar)**2)
    print "sstot: ",str(sstot)
    results['determination'] = ssreg / sstot

    print "results:", results
    return results

    
testX = [1,3,8,7,9]
testY = [10,12,24,21,34]

print "r: ",computeCorrelation(testX, testY)
print "r^2:",str(computeCorrelation(testX,testY)**2)

print polyfit(testX,testY,1)["determination"]